(i) Field of the Invention
This invention relates to a hammer for solid waste shredding, and in particular to a two-piece hammer including a replaceable wear tip removably mounted on the lower end of the hammer shank for shredding of solid waste, e.g. metal.
(II) Description of the Prior Art
Hammers with replaceable tips are well known, and various types are used for pulverizing or crushing materials. Shredding hammers are used in the scrap industry, and in particular in the scrap automobile industry. It is advantageous to use shredding techniques rather than compacting methods to dispose of scrapped metal objects, for example automobiles, since shredding permits the eventual separation and retrieval of the various materials in the automobile.
As a result of the particular structure of automobiles, it is desired to employ a shredding hammer which provides a large contact area on impact. However, this contact area is subject to extreme wear. The greater the contact area, the more effective is the operation of the hammer, with respect both to the shredding operation and to the expected life of the hammer.
During the operation of a conventional auto shredder, the hammers act as wearing parts coming in contact with the infeed material. The hammers are held onto a spinning rotor by shafts, of which there may be four or more, dependent on the design of the shredder. In conventional practice, once worn out, the hammers are removed by pulling the shafts out of the hammer holes. The old hammer is then thrown away.
(III) List of Prior Art Patents
Among the prior art patents disclosing hammers having a shank with a replaceable wear tip are the following Canadian patents:
No. 261,065 issued May 25, 1926 to G. P. Lucas; PA1 No. 417,341 issued Dec. 28, 1943 to The American Brake Shoe and Foundry Company; PA1 No. 417,342 issued Dec. 28, 1943 to The American Brake Shoe and Foundry Company; PA1 No. 450,604 issued Aug. 17, 1948 to Nordberg Manufacturing Company; PA1 No. 517,579 issued Oct. 18, 1955 to The Galigher Company; PA1 No. 526,473 issued June 19, 1956 to Bath Iron Works Corporation; PA1 No. 585,573 issued Oct. 20, 1959 to American Brake Shoe Company; PA1 No. 651,407 issued Oct. 30, 1962 to Poor & Company; PA1 No. 735,419 issued May 31, 1966 to L. E. Toews; PA1 No. 803,998 issued Jan. 14, 1969 to Abex Corporation; PA1 No. 803,999 issued Jan. 14, 1969 to Abex Corporation; PA1 No. 889,292 issued Dec. 28, 1971 to Abex Corporation; and PA1 No. 897,139 issued Apr. 4, 1972 to Abex Corporation; PA1 and the following United States patents: PA1 Nos. 3,455,040; 3,457,998; 3,685,178; 3,812,608; 2,904,907; 2,904,908; PA1 Nos. 2,951,300; 2,993,656; 3,107,455; 3,197,894; 3,129,899; 3,196,956; PA1 Nos. 3,254,726; 3,278,126; 3,236,463; 3,268,012; 3,459,998; 3,367,585; PA1 Nos. 3,410,010; 2,962,233; 2,994,486; 3,453,755; 3,834,764; 3,844,619; PA1 Nos. 3,904,247; 3,850,359; 3,410,010; 3,704,753; 3,097,259; 3,371,476; PA1 Nos. 3,371,436; 3,006,089; 3,774,324; 3,545,691; 3,503,562; and 3,738,586.
However, none of these patents disclose hammers having easily replaceable tips in which the tip is securely held in place. Moreover, present auto shredders do not use replaceable tip hammers extensively since the requirements of an easily replaceable tip having a large body contact area exposed to wear have not been met by any of the abovementioned known types of replaceable tip hammers.